/**
 *    ["@babel/plugin-proposal-decorators",{legacy:true}],
       ["@babel/plugin-proposal-class-properties",{loose:true}]
 */

       class Circle {
        PI = 3.14;
    }
    //转成ES5如何转的
    let c1 = new Circle();
    console.log(c1.PI);
    
    //loose=true
    function Circle(){
        this.PI = 3.15;
    }
    let c1 = new Circle();
    
    //loose=false
    function Circle(){
        Object.defineProperty(this,'PI',3.15);
    }
    
    
    @readonly
    class Cirlce2{
    
    }
    
    /* class @readonly Cirlce3{
    
    } */